Process for treating hydrocarbons



I Dec. 24,- 1940.

Original Filed July 23, 1935 rlxco GASES 2 Sheets-Sheet i LIGHTER 1 THAN GASOLINE VAPOR$ T CONDENSER Y 2 l2 ,\1 I2 ALIGHT GASES COMPRESSOR 2 a SEPARATOR STRIPPER CONDENSER I 11 HEAVY GASES 2.2 E-zzz;

v "23 2s 2 :5 :2 24 GAS 7 l s 27 7' g 27A O T 2| x SEPARATOR 9- l4 la $23 29 3| LIQUID PUMP t [ABSORPTION OIL GAS '5 4 STABLE t GASOLINE /LIGHT GASES PUMP ' a2 PQLYMERIZING con.

& HEAVlER/ ATTORNEYS.

Dec. 24, 1940.

fF'XED GASES 5O ABSORBER COMPRESSOR 2 Sheets-Sheet 2 55 1 SEPARA- TOR cowazssba ONIPRESSOR i or inal Filed July 23, 1935 M P YOUKER PROCESS FOR BR EATING HYDROC-ARBONS STRIP- PER CONDENSER {CONDENSER 49 1 RICH on.

STABIL- IZER amux SEHKRATOR ABSORPTION on.

LEAN OIL UNSATURATED HYDROCARIBONS-\ CONDENSEFI H IGH TEMPERATURE GOIL \LIGHT GASES L \GASOLINE a. HEAVIER 2M f/w/d q mR ATTORNEYS.

Patented Dec. 24, 1940 UNITED STATES PATENT OFFICE Phillips Petroleum Company, Bartlesville,

kla., a corporation of Delaware Application July 23, 1935, Serial No. 32,805 Renewed April 21, 1938 11 Claims.

This invention relates to a process of treatin hydrocarbons and relates particularly to a process for converting normally gaseous hydrocarbons to normally liquid hydrocarbons.

An object of the present invention is to provide a process for treating a mixture of normally gaseous hydrocarbons under a condition best suited to effect conversion of the individual hydrocarbons in the mixture to a maximum yield of normally liquid hydrocarbons.

More specifically an object of the present invention is to segregate lighter from heavier normally gaseous hydrocarbons contained in a starting mixture of such materials and to treat these groups both separately-and in combination to obtain an increased yield of liquid products therefrom.

In one form my new invention comprises the following steps, separation and removal of normally gaseous hydrocarbons such as ethane, propane and butane from gas mixtures also containing fixed gases such as methane, hydrogen etc.; division of the separated gases into a lighter portion consisting principally of ethane and propane and a heavier portion consisting largely of butane; subjection of the lighter portion to high temperature conditions suitable for converting the saturated hydrocarbons contained therein to the corresponding unsaturated hydrocarbons; mixing the resulting unsaturated hydrocarbons with the heavier portion of the gases previously separated from the original charge and converting the resulting mixture under conditions of temperature and pressure particularly suited to effect polymerization of this mixture to normally liquid hydrocarbons predominantly of the motor fuel range.

Other advantages of my new invention reside in the specific method of effecting, in an economic and efiicient manner, the separation of the normally gaseous materials into the aforementioned lighter and'heavier portions and in the combination of this method with the conversion steps themselves to produce a high yield of normally liquid hydrocarbons in the motor fuel range.

This specific method consists in abstracting the desired normally gaseous materials as well as heavier materials from a stream of gas such as natural gas which may be supplied directly from gas or oil wells, by absorption in a liquid absorbent under relatively high pressure; flashing of the enriched absorbent under somewhat lower pressure to separate therefrom the lighter normally gaseous fraction referred to above while retaining therein the heavier normally gaseous fraction and normally liquid materials: then flashing the partially denuded absorbent under still lower pressure to vaporize and strip the remaining absorbed material therefrom; then compressing these latter vapors and rectifying them to separate the said vapors into the aforementioned heavier normally gaseous portion and stable normally liquid material suitable for direct inclusion in motor fuel.

Some of the normally gaseous constituents recovered from the products of the subsequent conversion steps may be introduced into the above described absorption system to recover recycle material from these constituents without 15 the necessity of adding additional equipment for this purpose.

Other objects and advantages of my new invention will be readily apparent from the following description taken in conjunction with the go attached drawings which illustrate one diagrammatic form of apparatus which may be used for successfully practicing the invention.

Referring to the drawings hydrocarbon gas such as natural gas direct from gas or oil wells, cracking or crude still gases or the like, is delivered through a pipe I under relatively high pressure into an absorber 2. If the gas supply is not available under a sufiiciently; high pressure a pump 3 in pipe I may be utilized to increase the pressure of the gas. The gas entering absorber 2 fiows upward therethrough and is contacted therein with a down flowing stream of absorption oil which may be a product recovered from the process or extraneously introduced liquid suitable for this purpose. The initial quantity of absorption oil is introduced by way of pipe 4 in which is mounted a valve 5 and a pump 6 which pumps the absorption oil into the upper portion of absorber 2. The gas unabsorbed in absorber 2 passes therefrom through a pipe 1 in which is mounted a valve 8. Valve 8 is manipulated to hold any desired pressure on absorber 2. This pressure is usually sufliciently high to cause absorption of all of the constituents of the entering gas except the major portion of the methane and lighter fixed gases such as hydrogen, nitrogen, carbon dioxide, etc. and some of the ethane. All of the other constituents of the entering gas comprising part of the ethane, substantially all of the propane, butane and the heavier normally liquid materials are absorbed in the absorption oil and pass from absorber 2 through a pipe 9 in which is mounted a valve l0 into a separator H.

In passing from absorber 2 the pressure is reduced on the enriched liquid entering separator H and a portion of the absorbed material is flashed from the enriched oil as a result of the reduction in pressure, and passes from the separator ll through a pipe l2 in which is mounted a valve l3 which is manipulated to maintain such a pressure in separator II as to permit only a lighter portion of the normally gaseous materials contained in the enriched absorbent to vaporize in separator I This lighter portion of the normally gaseous materials comprising ethane and a portion of the propane and such smaller portions of butane and heavier fractions as may vaporize under the particular superatmospheric pressure and temperature employed, the temperature being generally atmospheric, will then be further processed as will be more fully described hereinafter.

The partially denuded absorption oil will be withdrawn from separator through a pipe l4 in which is mounted a valve MA and again flashed under further reduced pressure in a stripping chamber i5 wherein the remaining absorbed material is stripped from the absorption oil as a result of the reduction in pressure, assisted if necessary by heat applied in the stripper IE, or if desired by suction applied by a combination vacuum pump and compressor mounted in a pipe l6 which leads from the upper portion of stripper 5. The denuded absorption oil which will collect in the lower portion'of stripper l5 will be withdrawn therefrom through a pipe I 8 in which is mounted a valve I9 into pipe 4 by pump 8 which then recirculates the denuded oil to absorber 2. The stripped vapors removed in stripper l5 pass through pipe l6 and are compressed by compressor I! and d scharged into a stabilizing column 20 wherein these vapors, which contain the heavier portion 45. line, are fractionated to sharply separate the heavier normally gaseous materials consisting principally of butane and smaller amounts of propane from the normally liquid materials. Heat supplied by a heating coil 2| located in the lower portion of stabilizer 20 is used if necessary to assist in the separation. Vapors separated in stabilizer 20 pass upward therethrough and those which reach the upper portion thereof pass therefrom through a pipe 22. These vapors which comprise principally butane and some propane pass through a condenser 23 where the major portion of the butane is condensed leaving most of the propane uncondensed. The mixture of liquefied butane and uncondensed propane then passes into a separator 24 wherein the gaseous propane will separate from the liduefied butane and will pass from separator 24 through a pipe 25 and a valve 26 into pipe I 2 wherein the propane mixes with the similar light gases passing through pipe |2 as heretofore described and is conducted to further processing steps as will be later described. Valve 26 is manipulated to regulate the pressure in separator 24, condenser 23 and stabilizer 20 in any manner necessary to assist in effecting the desired separation in stabilizer 20. A portion of the liquefled butane which will collect in separator 24 will be returned therefrom through a pipe 21 and a valve 28 by a pump 21A to the upper portion of stabilizer 20 to serve therein as reflux,

suflicient liquid butane being thus returned to cause condensation in stabilizer 20 of all materials heavier than butane contained in the vapors flowing upward in stabilizer 20. The material thus condensed will consist principally of pentane and heavier natural gasoline fractions and will collect in the lower portion of stabilizer 20 whence it will be withdrawn through a pipe 29 by opening a valve 30 in pipe 29. The butanefree natural gasoline thus withdrawn may be utilized in any desired manner though it will usually be blended with the final gasoline prodnot of the system. The remainder of the liquid butane collecting in separator 24 will be withdrawn through a pipe 3| by opening a valve 32 and will be further processed in a manner subsequently to be described.

At this point in the process there are available two difierent materials for further processing. They are a lighter normally gaseous fraction comprising principally ethane and propane, available at this point in vapor form in pipe l2 and a heavier normally gaseous fraction comprising principally butane and some propane, available at this point in liquid form in pipe 3|.

Taking first the lighter normally gaseous fraction in pipe l2, this material Will be compressed by a compressor 33 in pipe l2 and will be pumped thereby through a heating coil 34 mounted in a furnace 35. In passing through the coil 34 the ethane-propane fraction will be heated to a high temperature sufficient to effect conversion of the ethane and propane to the corresponding unsaturated hydrocarbons, namely ethylene and propylene, forming at the same time some fixed gases and materials heavier than propylene. The heated and converted materials will then pass through a pipe 36 in which is mounted a valve 31 into a cooler 38. Valve 31 will be manipulated to hold pressure on the material passing through coil 34. The pressure required will usually be only sufficient to overcome the pressure drop through the succeeding portions of the apparatus but in some cases may be appreciably higher than the minimum pressure required to overcome such friction losses. Since the temperature required to convert ethane and propane to ethylene and propylene is quite high, ranging generally between 1000 F. and 1700 F. depending upon the pressure and the rate of conversion desired, in order to prevent secondary reactions such as excessive polymerization to tars and other heavy carbonaceous materials, rapid cooling of the products leaving coil 34 is usually necessary. To meet this condition cooler 38 may be of special design to efiect shock chilling as by direct mixing of cold oil or water with the products leaving coil 34. In any case the products are cooled below an active reaction temperature in cooler 38 from which the partially cooled materials pass through a pipe 39 which leads through a secondary condenser 40 wherein sufiicient additional cooling, if necessary, takes place to condense substantially all of the material heavier than gasoline formed in passage through the coil 34. The resulting heavy condensate together with uncondensed material which consists of the produced gasoline range material, ethylene and propylene, unconverted ethane and propane and fixed gases will pass into a separator 4| wherein the uncondensed material will separate from the relatively heavy normally liquid material. The normally liquid material comprising products generally heavier than gasoline will be removed from separator 4| through a pipe 42 by opening a valve 49 in pipe 42 and will be sent to further fractionating equipment as will be described hereinafter. The uncondensed material containing unsaturated hydrocarbons will be withdrawn 6 from separator 4| through a pipe 44 by a compressor 45 which will compress the unsaturated material to a relatively high superatmospheric pressure and discharge the compressed material into an absorber 46 wherein the compressed gases 10 will be contacted with a stream of absorption oil supplied through a pipe 41 and valve 49 by a pump 49. Such conditions of pressure and volume of absorbent will be maintained in absorber 46 as to cause the absorption oil to absorb substantially all of the ethane-ethylene, propanepropylene and heavier fractions contained in the gaseous material introduced into absorber 46 through pipe 44 and leave unabsorbed only fixed gases such as methane and lighter which will be discharged from absorber 46 through a pipe 59 in which is mounted a valve 5| which will be manipulated to hold any desired pressure on absorber 46. The fixed gases thus discharged may be vented to the fuel system or disposed of in any desired manner. The rich absorption oil containing the absorbed constituents will be withdrawn from absorber 46 through a pipe 52 by opening a valve 53 in pipe 52 and will be discharged into a separator 54 under a pressure somewhat reduced below that maintained in'absorber 46. The reduction in pressure effected in separator 54 may be of such degree as to permit flashing from the rich absorption oil of only the lighter fraction of the absorbed constituents, such for example as the ethane-ethylene fraction. These flashed vapors will separate from the partially denuded absorption oil in separator 54 and will be withdrawn therefrom through a pipe 55 in which is mounted a valve 56, by which the desired pressure in separator 54 may be maintained, to a compressor 51 in pipe 55 which will compress the flashed vapors and pump them through a condenser 58 wherein sufficient cooling will be applied to the compressed vapors to liquefy them, if desired, and pump the liquefied material through a pipe 59 and valve 69 into pipe 3| which leads to a further conversion step as will be subsequently described. Instead of discharging the cooled and compressed gas in pipe 59 into pipe 3|, valve 60 may be closed and the gases passed through a pipe 6| by opening a valve 62 in pipe 6| into pipe I! and may thus be recycled through the high temperature conversion coil 34. The partially denuded absorption oil in separator 54, containing the heavier portions of the absorbed gases such for example as the propanepropylene and butane-butylene and gasoline fractions will be withdrawn from separator 54 60 through a pipe 63 by opening a valve 63A in pipe 63 and will be discharged under still further reduced pressure into a stripper 64 wherein the remaining absorbed material will be stripped from the absorption oil which will then be with- 65 drawn from stripper 64 through a pipe 65 by opening a valve 66 in pipe 65 and returned to pipe 41, through which it will be recirculated to absorber 46 by pump 49 to be re-utilized therein in the manner previously described. The strip-- ping of the remaining absorbed material from the absorption oil in stripper 64 may be effected with the assistance of heat or by suction applied through a pipe 61 by a combination vacuum pump and compressor 68 which will withdraw I5 the stripped vapors from stripper 64, compress them to any desired pressure and introduce them into a stabilizer 69 wherein the compressed vapors will be fractionated to separate gasoline boiling range material from the lighter normally gaseous materials such as the propane-propylene 5 and butane-butylene fractions. The fractionation in stabilizer 69 may be assisted by heat supplied from a heating coil 19 located in the lower portion of stabilizer 69. The stabilized gasoline separated by fractionation in stabilizer 69 will 19 .be removed therefrom through a pipe II by opening a valve 12 and will be disposed of in any desired manner. Since it is a final product of the process it may be sent to storage or blended with the gasoline previously removed from stabilizer 15 29 or with additional gasoline recovered in other steps of the process to be described later.

The normally gaseous fractions separated from gasoline in stabilizer 69 will pass therefrom through a pipe 13 which leads through a conso denser I4 into a separator 15. The normally gaseousfractions will be at least partially condensed in condenser 14 and the mixture of condensate and uncondensed vapors will enter separator 15 wherein uncondensed vapors will sepa- 25 rate from condensed normally gaseous materials. Some of the condensed liquid in separator 15 will be returned to stabilizer 69 through a pipe 16 and valve 11 by a pump 16A to be utilized as reflux to effect the desired fractionation and sep- 30 aration of gasoline from lighter constituents in stabilizer 69. This reflux material will generally comprise the butane-butylene and propane-propylene fractions of the vapors passing from stabilizer 69. The remainder of this liquefied ma- 35 terial collecting in separator 15 and not utilized for reflux as described will be withdrawn from separator 15 through a pipe 18 and valve 19 and passed into pipe 59 and thence into pipe 3| for further processing as will be later described. The uncondensed vapors separated from the condensate'in separator I5 will be withdrawn there from through a pipe 96in which is mounted a valve 9|" which will be manipulated to maintain any desired pressure on stabilizer 69 and its at- 45 tendent auxiliary equipment. The vaporous fraction thus withdrawn will consist principally of the remainder of the ethane-ethylene fraction not previously removed in separator 54, and a portion of the propane-propylene fraction and 50 will be passed to pipe 55 to be further handled with the material passing through pipe 55 as previously described.

At this point in the process the following has been accomplished, a gas supply has been scrubbed 55 to remove substantially all the liquefiable materials contained therein and these materials have been separated into normally liquid materials and lighter and heaviernormally gaseous fractions, the lighter normally gaseous fraction containing 0 ethane, and propane principally has been subjected to a heating step to convert the major portion of these hydrocarbons to the corresponding unsaturated hydrocarbons which, after separation from fixed gases and normally liquid materials re- 65 sulting from the conversion reaction, are liquefied and mixed with the originally separated heavier normally gaseous fraction obtained from the initial charge to the process.

This latter mixture is that which is formed in pipe 3| as described above and the description will now proceed from that point. The mixture in pipe 3| which comprises the liquefied heavier portion of the normally gaseous hydrocarbons consisting principally of butane and propane obtained 80 into a separator 81. 'In passing through the coil 83, the liquefied gaseous materials will be subjected to a temperature ranging generally from 850 F. to 1150 F. and will be maintained under a pressure, regulated by means of valve 88, of above 500 pounds per square inch, usually between 1000 and 3000 pounds per square inch or even higher. Under these conditions the composite liquefied gases passing through coil 83 will be polymerized at least in part to normally liquid materials largely in the gasoline boiling range. Some fixed gases and materials heavier than gasoline will also be formed while some of the charge material may remain unconverted. Upon entering separator 81 the pressure upon the products of the polymerization reaction will be reduced and the products subjected to a fractionation operation to separate the gasoline and heavier materials from the materials lighter than gasoline which consist largely of butane and lighter normally gaseous materials. The gasoline and heavier materials will be withdrawn from separator 81 through a pipe 88 by opening a valve 89 in pipe 88 and will be fed into pipe 42 through which the heavier products obtained from the conversion operation in coil 34 as previously described are being conducted. The resulting mixture in pipe 42 is then conducted to a fractionator 90 wherein this mixture is subjected to a conventional fractionating operation to separate gasoline and anyv lighter materials which may be contained in the mixture from heavier products of the process. A heating coil 9| in fractionator 90 will supply any heat necessary to efiect eiiicient fractionation. The separated heavier products will be removed from fractionator 90 through a pipe 92 by opening a valve 93 in pipe 92 and will be disposed of in any desired manner.

The lighter than gasoline vapors separated from gasoline and heavier in separator 81 will pass therefrom through a pipe 94 and valve 95 thence through a condenser 96 wherein a portion of the vapors will be condensed and the resulting mixture of condensate and uncondensed vapors will flow from condenser 96 into a separator 91 wherein the condensate which will consist of the heavier portion of the vapors, usually butane and some propane, will separate from uncondensed vapors consisting usually of some propane, ethane and fixed gases. Some of the condensate will be withdrawn from separator 91 through a pipe 98 and valve 99 and will be returned to separator 81 to serve as reflux. Sufiicient material will be thus returned to condense substantially all the gasoline and heavier material in separator 81. The remainder of the condensate not utilized as reflux will be withdrawn from separator 91 through pipe I00 by opening valve IOI and will be returned to pipe 3I for recycling through the polymerization coil 83. The uncondensed vapors separated from condensate in separator 91 will be withdrawn therefrom through a pipe I 02 and a valve I03 by a compressor I04 which will compress these vapors and discharge them into pipe I, whereby they are reprocessed along with corresponding constituents recovered from the initial charge to the process as has heretofore been described. Valve I03 in pipe I02 will be manipulated to control the pressure under which the separation in separators 81 and 91 is effected. This will usually be sufficiently high to effect liquefaction of substantially all the butane and a large part of the propane in the vapors leaving separator 81 through pipe 94. Instead of separating the vapors leaving separator 81 into a heavier liquefied fraction and a lighter gaseous fraction all of the vapors may be passed directly from pipe 94 through a pipe I05 and a valve I08 into pipe I02, by closing valve 95. Thus all of these normally gaseous constituents will be mixed with the initial gas charge to the process and reprocessed therewith and the polymerizing operation in coil 83 will become a oncethrough operation instead of a recycling process.

The vapors separated from heavy products in fractionator 90 containing gasoline and some lighter constituents will pass from fractionator 90 through a pipe I01 which leads through a condenser I08 to a separator I09. In condenser I08 gasoline contained in the vapors will be condensed and in separator I 09 will separate from uncondensed gases and a portion of the gasoline will be withdrawn from separator I09 through a pipe I I0 and a valve III and will be returned to fractionator 90 to be utilized as reflux. Sufilcient gasoline will be thus returned to effect condensation in fractionator 90 of substantially all materials heavier than gasoline contained in the vapors passing upwards in fractionator 90.

The remainder of the gasoline which will collect in separator I09 will be withdrawn therefrom through a pipe I I2 and valve I I3 as a final product of the process. This gasoline may be sent to storage separately or it may be blended with the gasolines removed from stabilizers and 69 as previously described This blended material then becoming the ultimate product of the process.

The vapors lighter than gasoline separated from gasoline in separator I09 will be withdrawn therefrom through a pipe H4 and valve II5 into pipe I02 by means of compressor I04. The vapors will thus be mixed with those from separators 81 and 91 and will thus be returned to the initial steps of the process and subjected to complete reprocessing. Valve 5 will be manipulated to maintain any desired pressure on the fractionating system comprising fractionator 90 and its attendant equipment.

The pressures maintained in the absorption and fractionating system comprisingabsorber 2, separator II, stripper I5, stabilizer 20 and the interconnecting pipes, condensers etc. will vary depending on the composition of the charge, the degree of separation desired in vessels II and I5 and the degree of fractionation desired in stabilizer 20.

The pressure maintained on the absorption operation in absorber 2 will generally range. between 100 and 300 pounds per square inch or higher. The pressure in separator II will generally be at least 50 pounds lower than that in absorber 2 depending upon the composition desired in the light gas fraction to be removed from separator II.

The pressure in stripper I5 will be appreciably lower than that in separator II and may even be sub-atmospheric again depending upon what composition is desired in the heavy vapor fraction removed therefrom.

The pressure in stabilizer 20 will be generally substantially superatmospheric depending upon the degree and type fractionation desired. I have found that pressures above 100 pounds per square inch are generally to be desired in this stepof the process.

In general it may be stated that the separation to be effected in the absorption and stabilizer system is such as to remove from the inlet gas a major portion of the ethane fraction contained therein and substantially all of the fractions heavier than ethane, separation of the thus removed fractions into a lighter normally gaseous hydrocarbon fraction which lends itself most readily to conversion to corresponding unsaturated hydrocarbons without formation of excessive quantities of heavier materials, and a heavier normally gaseous fraction which may be readily polymerized to normally liquid hydrocarbons in a single step. These fractions when later processed as above described will produce a high yield of normally liquid hydrocarbons, the major portion of which will boil in the normal gasoline boiling range.

The pressures applied in absorber 46, separato 54, stripper 84 and stabilizer 69 will generally be of the same order as those applied in the initial absorption system as above described.

The pressures maintained in separators 81 and 91 will usually range between 100 and 300 pounds per square inch and those in fractionator 90 and separator I09 will usually range from substantially atmospheric to 100 pounds or more.

It will be evident that my process may be directly connected to a natural gas well and the natural gas from the well will be efliciently processed thereby to client conversion of a major portion thereof to gasoline and a minimum amount of fixed gas which in many cases will be sufficient only to supply the heat requirements of the process. The net result is that the entire production of a natural gas well will be entirely converted to the much move valuable gasoline without the excessive waste of natural gas which now occurs to the great detriment of this important natural resource.

Instead of polymerizing together in coil 83 the unsaturated hydrocarbons formed by the conversion in coil 34 and the heavier normally gaseous hydrocarbons removed from separator 24 through pipe 3|, it may be found advisable to separately polymerize each of these materials, although I consider it more advantageous to polymerize the mixture of these materials in the manner described. Similarly other variations may be made in my new process without departing from the spirit and scope of my invention as defined by the appended claims.

I claim:

1. The process for the conversion of normally gaseous hydrocarbons to normally liquid hydrocarbons, which comprises separating said normally gaseous hydrocarbons in an oil absorption step into an initial lighter portion of gases, and a heavierportion of gases, subjecting said heavier portion of gases to a polymerization step, separating unconverted light gases from the eflluents of hydrocarbons, treating eilluents from said conversion step in a second oil absorption step to separate the same into unsaturated hydrocarbons and light gases, recycling said light gases in said conversion step, and adding said unsaturated hydrocarbons to said heavier portion of gases for treatment in said polymerization step.

2. A process for the conversion of normally gaseous hydrocarbons to normally liquid hydrocarbons which comprises separating said normally gaseous hydrocarbons into an initial lighter portion of gases, and a heavier portion of gases, subjecting said heavier portion of gases to a polymerization step, separating unconverted gases from the eiliuents of said polymerization step and recovering from said eiliuents a desired normally liquid hydrocarbon, recycling a portion of said unconverted gases through said first mentioned separation step, condensing a second portion of said unconverted gases and recycling them through said polymerization step, subjecting said initially lighter portion of gases to a conversion step to effect a partial conversion thereof into unsaturated normally gaseous hydrocarbons, treating the efiiuents from said conversion step in a separation step to separate the same into unsaturated hydrocarbons and light gases, and adding said unsaturated hydrocarbons to said heavier portion of gases for treatment in said polymerization step.

3. A process for the conversion of normally gaseous hydrocarbons to normally liquid hydrocarbons which comprises separating said normally gaseous hydrocarbons into an initial lighter portion of gases, and a heavier portion of gases, subjecting said heavier portion of gases to a polymerization step, separating unconverted gases from the efliuents of said polymerization step and recovering from said effluents a desirable normally liquid hydrocarbon, recycling a portion of said unconverted gases through said first mentioned separation step, condensing a second portion of said unconverted gases and recycling them through said polymerization step, subjecting said initially lighter portion of gases to a conversion step to effect a partial conversion thereof into unsaturated normally gaseous hydrocarbons, treating the eilluents from said conversion step in a separation step to separate the same into unsaturated hydrocarbons and light gases, recycling said light gases in said conversion step, and adding said unsaturated hydrocarbons to said heavier portion of gases for treatment in said polymerization step.

4. A process for the conversion of normally gaseous hydrocarbons to normally liquid hydrocarbons, which comprises separating said normally gaseous hydrocarbons into a lighter portion and a heavier portion, subjecting said lighter portion to conversion conditions sufficient to convert a part thereof to unsaturated normally gaseous hydrocarbons, separating from the efiiuent of the said conversion step a fraction containing said unsaturated hydrocarbons and relatively free of methane and hydrogen, and subjecting said fraction together with said heavier portion to polymerization conditions to produce liquid hydrocarbons from the resulting mixture.

5. The process for the conversion of normally gaseous hydrocarbons to normally liquid hydrocarbons which comprises separating said normally gaseous hydrocarbons into a lighter and a ly gaseous hydrocarbons, separating and removing from the products of conversion a fraction containing subtantially all of said unsaturated hydrocarbons relatively free of hydrogen and methane, and subjecting unsaturated hydrocarbons together with said heavier portion to polymerization conditions to convertthe resulting mixture to normally liquid hydrocarbons.

6. The process for'the conversion of normally gaseous hydrocarbons to normally liquid hydrocarbons which comprises separating said normally gaseous hydrocarbons into a lighter and a heavier portion, subjecting said lighter portion to conversion conditions suitable to effect conversion of a part thereof to unsaturated normally gaseous hydrocarbons, independently separating and removing from the products of conversion a fraction containing substantially all of said unsaturated hydrocarbons relatively free of hydrogen and methane, and subjecting unsaturated hydrocarbons together with said heavier portion to polymerization conditions to convert the resulting mixture to normally liquid hydrocarbons.

'7. The process for the conversion of normally gaseous hydrocarbons to normally liquid hydrocarbons, which comprises subjecting a mixture of normally gaseous hydrocarbons containing normally liquid hydrocarbons to an oil absorption step conducted under relatively high pressure to separate therefrom a mixture of normally gaseous hydrocarbons and normally liquid hydrocarbons, separating said latter mixture under reduced pressure into a normally liquid fraction, a lighter normally gaseous fraction and a heavier normally gaseous fraction, subjecting said heavier normally gaseous fraction to polymerization conditions under relatively high pressure to convert a portion thereof to normally liquid hydrocarbons, subjecting said lighter normally gaseous fraction to high temperature to effect conversion of at least a portion thereof to unsaturated normally gaseous hydrocarbons, separating and removing from the products of conversion a fraction containing substantially all of saidunsaturated hydrocarbons relatively free of hydrogen and methane, and subjecting said unsaturated normally gaseous hydrocarbons to said polymerization conditions concurrently with said heavier normally gaseous fraction.

8. The process for the conversion of normally gaseous hydrocarbons to normally liquid hydrocarbons, which comprises separating said normally gaseous hydrocarbons into a lighter and a heavier portion, subjecting said lighter portion to conversion conditions to effect a partial conversion thereof to unsaturated normally gaseous hydrocarbons, separating and removing from the products of conversion a fraction containing substantially all of said unsaturated hydrocarbons relatively free of hydrogen and methane, subjecting said unsaturated hydrocarbons together with said heavier portion to polymerization conditions to convert the resulting mixture to normally liquid hydrocarbons, and separating theeffluents of said polymerization into a desirable normally liquid hydrocarbon and unconverted hydrocarbon gases and recycling said gases through said polymerization step,

9. The process for the conversion of normally gaseoushydrocarbons to normally liquid hydrocarbons, which comprises separating said normally gaseous hydrocarbons into a lighter and a heavier portion, subjecting said lighter portion to conversion conditions suitable to effect a partial conversion thereof to unsaturated normally baseous hydrocarbons, separating from said unsaturated normally gaseous hydrocarbons a second portion of lighter gases and subjecting said second portion of lighter gases to said conversion conditions, and subjecting said unsaturated hydrocarbons together with said heavier portion to polymerization conditions to convert the resulting mixture to normally liquid hydrocarbons.

10. The process of converting gas mixtures, containing chiefly C2, C3 and C4 hydrocarbons, to liquid hydrocarbons which comprises separating the mixture into a fraction containing chiefly heavier components of said mixture and another fraction containing the lighter components, subjecting each fraction in a separate zone to suitable conditions of time, temperature and pressure for converting the gaseous constituents to liquid hydrocarbons boiling within the gasoline boiling range, separating the bulk of the unconverted light gases from the reaction products of the light gas fraction conversion step, charging at least a portion of the products resulting from said conversion of the lighter gases to a common fractionating zone together with reaction products of the heavier gas fracion, separating the incondensible gases from the normally liquid hydrocarbons, and mixing the incondensible gases with a the fresh gas prior to separation thereof into fractions. 7

11. The process of converting gas mixtures, containing chiefly C2, C3, and C4 hydrocarbons, to liquid hydrocarbons which comprises separating said mixtures to provide a light gas fraction and a heavy gas fraction, subjecting each fraction in a separate zone to conditions of time, temperature and pressure suitable for converting at least a portion of the gaseous constituents to liquid hydrocarbons boiling within the gasoline range, separating the eiliuent of the light gas conversion step into a liquid fraction and a vaporous fraction, passing the liquid fraction together with the conversion products of the heavy gas fraction conversion step to a common fractionating zone, separating the incondensible gases from the normally liquid hydrocarbons, and mixing the incondensible gases with the fresh feed gas prior to separation thereof into fractions.

MALCOLM P. YOUKER. 

